Add docker container generation scripts (#5898)

These scripts generate the image we used to test flutter/engine in Cirrus.

ci/README.md

+This directory includes scripts and tools for continuous integration tests.

ci/docker/build/Dockerfile

+FROM ubuntu:14.04
+
+ENV DEPOT_TOOLS_PATH $HOME/depot_tools
+ENV ENGINE_PATH $HOME/engine
+
+RUN apt-get update
+RUN apt-get install -y git wget curl unzip python lsb-release sudo
+
+RUN git clone https://chromium.googlesource.com/chromium/tools/depot_tools.git $DEPOT_TOOLS_PATH
+ENV PATH $PATH:$DEPOT_TOOLS_PATH
+
+RUN mkdir --parents $ENGINE_PATH
+WORKDIR $ENGINE_PATH
+ADD engine_gclient .gclient
+RUN gclient sync
+
+WORKDIR $ENGINE_PATH/src
+RUN ./build/install-build-deps.sh --no-prompt
+RUN ./build/install-build-deps-android.sh --no-prompt
+
+WORKDIR $HOME/dart
+RUN wget https://storage.googleapis.com/dart-archive/channels/dev/release/2.0.0-dev.63.0/sdk/dartsdk-linux-x64-release.zip
+RUN unzip dartsdk-linux-x64-release.zip
+ENV PATH $PATH:$HOME/dart/dart-sdk/bin
+

ci/docker/build/README.md

+This directory includes scripts to build the docker container image used for
+building flutter/engine in our CI system (currently [Cirrus](cirrus-ci.org)).
+
+In order to run the scripts, you have to setup `docker` and `gcloud`. Please
+refer to the [internal flutter team doc](go/flutter-team) for how to setup in a
+Google internal environment.
+
+After setup,
+* edit `Dockerfile` to change how the container image is built.
+* run `./build_docker.sh` to build the container image.
+* run `./push_docker.sh` to push the image to google cloud registry. This will
+  affect our CI tests.
+

ci/docker/build/build_docker.sh

+#!/bin/bash
+
+# pull to make sure we are not rebuilding for nothing
+docker pull gcr.io/flutter-cirrus/build-engine-image:latest
+
+docker build --tag gcr.io/flutter-cirrus/build-engine-image:latest .
+

ci/docker/build/engine_gclient

+solutions = [{
+  "name"        : "src/flutter",
+  "url"         : "https://github.com/flutter/engine.git",
+  "deps_file"   : "DEPS",
+  "managed"     : False,
+  "safesync_url": "",
+}]

ci/docker/build/push_docker.sh

+#!/bin/bash
+
+docker push gcr.io/flutter-cirrus/build-engine-image:latest
+

travis/licenses_golden/licenses_flutter

@@ -189,6 +189,8 @@ ORIGIN: ../../../LICENSE
 TYPE: LicenseType.bsd
 FILE: ../../../flutter/.cirrus.yml
 FILE: ../../../flutter/DEPS
+FILE: ../../../flutter/ci/docker/build/Dockerfile
+FILE: ../../../flutter/ci/docker/build/engine_gclient
 FILE: ../../../flutter/lib/io/dart_io.cc
 FILE: ../../../flutter/lib/io/dart_io.h
 FILE: ../../../flutter/lib/snapshot/libraries.json